In recent years, various cell phones including smart phones, smart pads and the like, and various display devices such as MP3 players, PDAs, navigation systems and the like have been increasingly used with the sudden advent of information age. However, since most of these display devices are expensive electronic products, users feel the necessity of protecting these display devices from scratches or external impacts and decorating the display devices in order to make the appearances of the display devices better.
In particular, since liquid crystals disposed on the entire surface of the display device are exposed to strong external impacts in a defenseless state, the liquid crystals may be easily broken, and the broken liquid crystals should be replaced with new liquid crystals, or the display device itself should be optionally replaced with new one, which leads to an enormous increase in repair cost.
Therefore, strengthened glass panels are being currently launched to facilitate protection of the liquid crystals disposed on a surface of the display device. For example, conventional liquid crystal protection films respond to weak impact such as scratches, but strengthened glass protection panels serve to prevent damage of expensive liquid crystals by protecting the liquid crystals from strong external impacts. As a result, the strengthened glass protection panels have received an enthusiastic attention from consumers.
That is, the strengthened glass panel is formed with strengthened glass to reinforce the surfaces of liquid crystals so that the strengthened glass is attached to a surface of a display device to prevent the liquid crystals from being broken or scratched when the display device such as a smart phone is dropped from a high place.
However, strengthened glass panels that are being currently launched are inferior in quality since a double-coated adhesive tape is attached to the rear surface of strengthened glass, and thus have problems in that air bubbles may be easily generated when such a strengthened glass panel is attached to a surface of the display device, the double-coated adhesive tape is not easily detached due to its adhesivity when it is once attached to the display device, and residual adhesive components are left on the surface of the display device even when it is detached from the display device, thereby giving an unpleasant feeling about the appearance of the display device.
Therefore, Registered Utility Model No. 20-0452552 discloses a liquid crystal protection plate in which a double-coated adhesive tape is coated on portions of edges of strengthened glass without applying the double-coated adhesive tape to the entire rear surface of the strengthened glass. However, the liquid crystal protection plate has a problem in that a central region of the liquid crystal protection plate may be convexly lifted since the central region of the liquid crystal protection plate is not closely adhered to surfaces of the liquid crystals in the display device.
Accordingly, there is a demand for a strengthened glass panel which can be closely attached to a surface of the display device and easily detached from the surface of the display device.